ARTHROPOD BIOLOGY Cotton Balls as an Oviposition Substrate for Laboratory Rearing of Phytophagous Stink Bugs (Heteroptera: Pentatomidae) 1 2 FLA´ VIA A. C. SILVA AND ANTOˆ NIO R. PANIZZI Ann. Entomol. Soc. Am. 100(5): 745Ð748 (2007) ABSTRACT Studies were conducted to test the suitability of absorbent cotton as an oviposition Downloaded from https://academic.oup.com/aesa/article/100/5/745/8415 by guest on 28 September 2021 substrate for phytophagous stink bugs (Heteroptera: Pentatomidae). In conÞned boxes, Ͼ80% of total egg masses of Euschistus heros (F.), Dichelops melacanthus (Dallas), and Thyanta perditor (F.) were laid on cotton; for Piezodorus guildinii (Westwood) and Chinavia impicticornis (Stål), Ͼ60%. However, Nezara viridula (L.) and Edessa meditabunda (F.) did not oviposit on cotton balls, but instead on the box walls, on Þlter paper, or on food. Newly hatched nymphs successfully (Ͼ95%) left the eggshells despite the presence of cotton Þbers around the egg masses. KEY WORDS stink bug, egg deposition, soybean, cotton, insect rearing One of the critical issues when rearing phytopha- Materials and Methods gous stink bugs is to provide a suitable ovipositional Insect Colonies. Adults were Þeld-collected by substrate. Heteropterans oviposit on paper towels using a sweep net on wild [siberian motherwort, suspended inside cages or on draped strips of Leonurus sibiricus L., hairy beggarticks, Bidens cheesecloth (Shearer and Jones 1996, Bundy and pilosa L.] and cultivated [soybean; corn, Zea mays McPherson 2000). Bugs also oviposit on artiÞcial (L.)] host plants during December 2005ÐJanuary substrates such as plastic structures that mimic soy- 2006 in Londrina, PR, Brazil (latitude 23Њ 18Ј S). bean, Glycine max (L.) Merrill, leaßets by laying Colonies of seven stink bug species [Euschistus eggs on the lower (abaxial) surface (Panizzi et al. heros (F.), Dichelops melacanthus (Dallas), China- 2000). via impicticornis (Stål), Thyanta perditor (F.), More recently, an ovipositional substrate has been Piezodorus guildinii (Westwood), Edessa medit- developed for the southern green stink bug, Nezara abunda (F.), and Nezara viridula (L.)] were estab- viridula (L.), that consists of cheesecloth (Fisher, lished in the laboratory at the Embrapa National Pittsburgh, PA) stretched tightly over wooden em- Soybean Research Center facilities. They were fed broidery rings and treated with extracts from soybean fresh green bean, Phaseolus vulgaris L., pods; raw plants (Panizzi et al. 2004). These extracts, particularly shelled peanuts, Arachis hypogaea L.; mature soy- those from soybean pods extracted using methanol, bean seeds; and fruits (berries) of privet, Ligustrum yielded the best results, and they are under investi- lucidum Aiton, which were replaced every 2 d. Sev- gation to identify the chemicals eliciting positive re- eral pairs (n ϭ 20Ð30) of each species were placed sponses. in transparent plastic containers (20 by 20 by 24 cm; While keeping a colony of the Neotropical brown three containers/species) covered with a meshed stink bug, Euschistus heros (F.) in the laboratory, we lid. With two exceptions, the colonies were main- noticed that females preferred to oviposit on the tained without introduction of feral insects for 6 mo, wet cotton used to provide water. From this casual to provide healthy laboratory-reared adults for the observation, we decided to test commercial cotton test. The exceptions were the colonies of E. medit- (dry) as an ovipositional substrate for several stink abunda and of C. impicticornis to which Þeld-col- bug species, in routine rearing. The rationale for lected adults were added because of high mortality testing dry cotton as an ovipositional substrate was of nymphs. its convenience, acceptability by the bugs, and po- Oviposition Site. Ten pairs of each species were tential use of a material that is clean and disposable. selected from the rearing colonies and placed indi- vidually in a translucent plastic box (11 by 11 by 3.5 cm) lined with Þlter paper and covered with a lid. Food (green bean pod, mature seeds of soybean, 1 Universidade Federal do Parana´, Departamento de Zoologia, and raw shelled peanut) and a ball (5 cm in diam- Caixa Postal 19020 Curitiba 81531-990, PR, Brazil. eter) of commercial absorbent cotton (Cremer S.A., 2 Corresponding author: Embrapa Soja, Laborato´rio de Entomolo- gia, Caixa Postal 231, Londrina 86001-970, PR, Brazil (e-mail: Blumenau, SC, Brazil) were added. The boxes were [email protected]). observed daily for 16 d. Food was replaced every 0013-8746/07/0745Ð0748$04.00/0 ᭧ 2007 Entomological Society of America 746 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 100, no. 5 Cotton Paper Box Food 120 a a a a a 100 a a 80 60 b b b 40 b b b 20 c b b Mean number of egg cluster (%) cluster egg of number Mean c c c c d c c c c c c c c Downloaded from https://academic.oup.com/aesa/article/100/5/745/8415 by guest on 28 September 2021 0 s is eros ildinii icorn u iridula canthu t abunda v E. h a ic t . l T. perditor P. g di N mp e . m D. me C. i E Fig. 1. Ovipositional preference between cotton balls, paper, box, and food in the laboratory of seven stink bug species. Means followed by the same letter do not differ signiÞcantly, using the Tukey test (P ϭ 0.05). other day, and the cotton ball was changed daily. The remaining two species, E. meditabunda and N. The number of egg masses laid on the cotton ball, viridula, did not oviposit on the cotton balls. E. and on Þlter paper, food, and walls and lid of the meditabunda oviposited preferentially on the box, plastic box was recorded daily, and the percentages followed by the food, but they did not oviposit on were calculated. All maintenance of adults and test- the Þlter paper. N. viridula oviposited preferentially ing were conducted in a walk-in environmental on the box, followed by the Þlter paper, but they did chamber [25 Ϯ 1ЊC, 60 Ϯ 10% RH, and a photoperiod not oviposit on the cotton balls or food (Fig. 1). That of 14:10 (L:D) h]. E. meditabunda did not oviposit on cotton balls, Data Analyses. The mean percentages of egg despite its small-size egg cluster (12Ð14 eggs dis- masses laid on cotton balls and on the walls and lid posed in two rows; Rizzo 1976), may be related to of the plastic box, Þlter paper or food, by each the size of eggs; E. meditabunda eggs are larger than species, were analyzed with analysis of variance those of the other species, which may prevent them (ANOVA). Means were transformed to arcsine be- from being glued to the irregularly disposed cotton fore using the Tukey test for multiple means (P ϭ Þbers. 0.05) comparison, which was performed using The southern green stink bug did not oviposit on the program STATISTICA, version 6.0 (StatSoft the cotton balls, probably because of the shape and 2001). size of its egg clusters (usually Ͼ100 eggs deposited in Þve to seven rows; Rizzo 1976); this egg mass requires a more even surface to be properly accom- Results and Discussion modated, as is the case with soybean leaßets, a Of the seven species of stink bug, Þve species (i.e., natural substrate (Todd 1989), or an artiÞcial sub- E. heros, D. melacanthus, C. impicticornis, T. perditor, strate made up of stretched cheesecloth (Panizzi et and P. guildinii) showed a variable (65Ð95%) and sig- al. 2004). niÞcant (P ϭ 0.05) preference for cotton balls as an Several egg clusters were placed together on cot- ovipositional site (Fig. 1). These same species also ton balls by E. heros (Fig. 2A), cotton Þbers were oviposited on the Þlter paper, but only C. impicticornis found around the eggs (Fig. 2B), and several Þbers also oviposited on the box. No bugs laid eggs on the fused to the bottom of the eggs (Fig. 2C); yet, newly food (green bean pod, and mature seeds of soybean hatched nymphs easily managed to move atop the and peanut). In general, these stink bug species lay egg eggshells (Fig. 2D). Preliminary tests indicate that clusters of no Ͼ25 eggs, with few rows. For example, survivorship of nymphs is not affected by the Þbers E. heros deposit egg clusters with three to 14 eggs in (95.7%; on soybean leaßets, 97.0%). two to three rows (Villas Boˆas and Panizzi 1980); D. Bundy and McPherson (2000) used draped strips melacanthus Þve to 14 eggs in three rows (F.A.C.S. and of cheesecloth, to obtain egg clusters of several A.R.P., unpublished data); C. impicticornis 12Ð14 eggs species of stink bugs in the laboratory. Strips of in three to four rows (Grazia et al. 1982); T. perditor cheesecloth are apparently a suitable substrate for 11Ð25 eggs in two rows (Panizzi and Herzog 1984), and egg deposition; however, these authors mention P. guildinii 11Ð15 eggs in two rows (Panizzi and Smith that egg clusters were loosely arranged in a some- 1977). what irregular pattern on cheesecloth strips. Addi- September 2007 SILVA AND PANIZZI:COTTON BALLS AS AN OVIPOSITION SUBSTRATE FOR STINK BUGS 747 Downloaded from https://academic.oup.com/aesa/article/100/5/745/8415 by guest on 28 September 2021 Fig. 2. Eggs of E. heros laid on cotton balls. (A) Egg clusters atop cotton Þbers (20ϫ). (B) Scanning electron microscopy of cotton Þbers below and around eggs (40ϫ). (C) Enlarged view of cotton Þbers glued to the egg bottom (note arrows) (150ϫ). (D) Newly hatched nymphs emerging from egg shells (20ϫ). tional studies are needed to compare cotton balls Embrapa National Soybean Research Center, Londrina, with cheesecloth (whether stretched or not) as an PR, Brazil.